Abstract
Littermate male S-D rats were maintained on either low Na (LS) or normal Na (NS) intake between ages 3-7 weeks and then switched to high Na intake between ages 7-9 weeks. The LS group showed retarded growth between 3-7 weeks of age, and a massive weight gain within a week after the switch to the high Na intake. The ECF compartment, determined by the distribution (4 hour phase) of injected 22Na, and the exchangeable 23Na (Exc. Na) were measured before the transition to the high Na diet, as well as at 8 and 9 weeks of age. The ECF (table; ml/kg BW; x ± SEM) at age 7 weeks was reduced in the LS group. Both the NS and LS groups manifested expansion of their ECF a week after the switch to the high Na intake. This compartment was, however, greater in the LS group. At age 9 weeks, despite a continuous high Na intake, the ECF of the NS rats returned to its original volume, whereas that of the LS group was still increased. Similar changes were noted in Exc. Na. These alterations were not shown in adult rats. It is concluded that in the developing rat chronic Na deficit alters the adaptation to Na excess in later life. Since the kidney is a major regulator of the ECF and body Na, this phenomenon may relate to modification of the renal handling of Na.
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Aviv, A., Kobayashi, T. & Levine, O. 1481 THE EFFECT OF TRANSITION FROM CHRONIC Na DEFICIT TO Na EXCESS IN THE DEVELOPING RAT. Pediatr Res 15 (Suppl 4), 690 (1981). https://doi.org/10.1203/00006450-198104001-01510
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DOI: https://doi.org/10.1203/00006450-198104001-01510